Wind turbine blade

Abstract

Wind turbine blade comprising at least one deformable trailing edge section having a plurality of actuators consecutively arranged substantially downstream from one another and a control system for controlling the actuators, wherein a downstream end of one actuator is connected by a substantially rigid link with an upstream end of the next actuator and the plurality of actuators comprises an upper actuator being mounted above a chord line of the blade section and a lower actuator being mounted below a chord line of the blade section. Wind turbines comprising such a blade and methods of controlling loads on a wind turbine blade are also described.

The invention claimed is: 
     
       1. A wind turbine blade,
 comprising at least one deformable trailing edge section having
 a plurality of actuators consecutively arranged substantially downstream from one another, and 
 a control system for controlling the actuators, 
 wherein a downstream end of one actuator is connected by a rigid link with an upstream end of a next actuator and the plurality of actuators comprises at least one upper actuator mounted above a chord line of the blade and at least one lower actuator being mounted below the chord line of the blade. 
 
 
     
     
       2. The wind turbine blade of  claim 1 , wherein the actuators are consecutively arranged as alternatingly upper and lower actuators. 
     
     
       3. The wind turbine blade of  claim 2 , wherein the actuators are linked such that upon activation of the at least one upper and/or the at least one lower actuator a structural shape of the blade trailing edge section changes in at least two degrees of freedom. 
     
     
       4. The wind turbine blade of  claim 2 , wherein the at least one upper actuator is mounted close to an inner surface of a suction side of a skin of the trailing edge section and the at least one lower actuator is mounted close to an inner surface of a pressure side of the skin. 
     
     
       5. The wind turbine blade of  claim 2 , wherein the rigid link comprises a plurality of rigid links connected to the actuators, wherein the rigid links connected to the upstream end of the actuators are mounted substantially perpendicular to a skin of the trailing edge section. 
     
     
       6. The wind turbine blade of  claim 1 , wherein the actuators are linked such that upon activation of at least one upper and/or at least one lower actuator a structural shape of the trailing edge section changes in at least two degrees of freedom. 
     
     
       7. The wind turbine blade of  claim 6 , wherein the actuators are linked such that upon activation of the at least one upper and/or the at least one lower actuator at least one of a flap angle and a chord length of the blade is changed. 
     
     
       8. The wind turbine blade of  claim 1 , wherein the at least one upper actuator is mounted close to an inner surface of a suction side of a skin of the trailing edge section and the at least one lower actuator is mounted close to an inner surface of a pressure side of the skin. 
     
     
       9. The wind turbine blade of  claim 8 , wherein the actuators are mounted substantially parallel to the skin. 
     
     
       10. The wind turbine blade of  claim 1 , wherein the rigid link comprises a plurality of rigid links connected to the actuators, wherein the rigid links connected to the upstream end of the actuators are mounted substantially perpendicular to a skin of the trailing edge section. 
     
     
       11. The wind turbine blade of  claim 1 , wherein the actuators are selected from among a group consisting of piezoelectric elements, bistable elements, pneumatic actuators and hydraulic actuators. 
     
     
       12. The wind turbine blade of  claim 1 , wherein a length of the trailing edge section extending from a trailing edge end towards a tip of the blade is equal to at least one third of a total length of the blade. 
     
     
       13. The wind turbine blade of  claim 1 , wherein a length of the trailing edge section is equal to between 30% and 40% of a chord line of the blade. 
     
     
       14. The wind turbine blade of  claim 1 , wherein at least a portion of a skin of the trailing edge section not supporting the actuators nor the rigid link is made of a relatively flexible material. 
     
     
       15. The wind turbine blade of  claim 14 , wherein substantially the whole skin is made of the relatively flexible material. 
     
     
       16. The wind turbine blade of  claim 14 , wherein at least inner areas of the trailing edge section next to the flexible material are filled with an anisotropic material. 
     
     
       17. The wind turbine blade of  claim 16 , wherein the anisotropic material is a honeycomb structure. 
     
     
       18. A wind turbine comprising at least one blade according to  claim 1 . 
     
     
       19. A method of controlling loads on the wind turbine blade according to  claim 1 , wherein the method comprises activating the at least one upper and/or the at least one lower actuator such that a structural shape of the trailing edge section changes in at least two degrees of freedom. 
     
     
       20. The method of  claim 19 , wherein the actuators are consecutively arranged as alternatingly upper and lower actuators.